Introduction: Laser is an acronym for "light amplification by stimulated emission of radiation." They are being developed for a variety of uses in periodontal therapy. The diode laser in dentistry is used for treatment of diseased periodontal soft tissue, allowing significant bacterial reduction, and removal of the inflammatory products while creating excellent hemostasis. A flexible fiber optic delivery system allows the clinician easy and safe access around the periodontal pocket. The wavelengths are transmitted through water and are very poorly absorbed in apatite crystals, making them an excellent choice to use in a periodontally involved sulcus that has inflamed tissue and pigmented bacteria. This study was undertaken to evaluate the effectiveness of diode laser as an adjunct to scaling and root planing (SRP) in the nonsurgical treatment of chronic periodontitis. Aim: To evaluate the effectiveness of diode laser on plaque index (PI), gingival index (GI) probing pocket depth (PPD) and clinical attachment level (CAL) in chronic periodontitis patients and to compare the outcome with SRP alone. To evaluate the efficacy of diode laser on plaque microorganisms namely Aggregatibacteractinomycetemcomitans and Prevotellaintermedia. Materials and Methods: A total number of 20 generalized chronic periodontitis patients were selected for the study. A randomized split-mouth design was followed to assign quadrants in each to one of the two treatment groups: SRP alone (Group I control group) and diode laser as an adjunct to SRP (Group II test group). The assessment of clinical parameters was carried out at baseline, day 30, 90, and 180. The microbiological analysis was done prior to the start of the treatment at baseline, day 15, 30, 90, and 180, respectively. Results: At baseline mean colony count was equal in both groups, however, at all the subsequent time intervals, mean colony count was lower in Group II as compared to Group I. All the groups showed statistically significant reduction in relation to PI, GI, PPD, CAL, and microbial count. Discussion: In this study, an attempt was made to evaluate the adjunctive role of diode lasers on gingival inflammation, pocket probing depth, the level of clinical attachment, and microbial count in relation to SRP using a case-control design. Recently, the use of laser has emerged as an adjunctive procedure in enhancing the clinical outcome of the periodontal treatment. It is one of the most promising new technical modalities for nonsurgical periodontal treatment and has an advantage of reaching sites that cannot be approached by conventional mechanical instrumentation. Conclusion: In the present study, an attempt was made to evalute the adjunctive role of diode lasers on plaque index, gingival index, pocket probing depth, level of clinical attachment and microbial count in relation to scaling and root planning using a case-control design. On the basis of these findings, adjunctive treatment with diode laser at a higher but clinically safe frequency (940nm) at repeated intervals showed a better efficacy in ensuring a better periodontal health as compared to SRP alone.

Knowledge of the transition from health to disease and the progression of the disease through various stages of severity are important in the development of effective strategies for prevention and treatment. [1] Several treatment modalities are available to achieve these goals which can be broadly classified into either surgical or nonsurgical approaches. [2] Reduction of the bacterial load utilizing laser systems in can be an effective tool when used as an adjunct to conventional treatment. [3]

The diode laser is a soft tissue laser having a wavelength of 810 nm or 910-980 nm. [4] The laser beam aids in soft tissue curettage, sulcular debridement, has a bactericidal effect [5] and has no interaction with dental hard tissues. During irradiation a part of the laser energy scatters and penetrates into periodontal pockets, stimulating the cells of surrounding tissues. This results in reduction of the inflammatory conditions, increased in cell proliferation, flow of lymph, improving the periodontal tissue attachment and marked reduction in postoperative pain. [6]

To evaluate the efficacy of diode laser on plaque microorganisms namely Aggregatibacteractinomycetemcomitans and Prevotellaintermedia.

Inclusion criteria

Patients with generalized chronic periodontitis

Patients with at least two nonadjacent sites per quadrant with PPD of ≥5 mm

Patients who have not undergone periodontal therapy in the past 6 months

Subjects who have not taken antibiotics medication 3 months prior to the study.

Exclusion criteria

Subjects who are chronic smokers and tobacco users

Patients with acute intraoral lesions

Patients with Grade III tooth mobility.

Review of literature

Extensive research continues to be done to study the possible effects of nonsurgical management in the improvement of clinical parameters and in the eradication on microbial colonies. Recently, laser therapy concept was introduced as an adjunct to SRP.

Moritz etal. 1997 evaluated the immediate effect of the diode laser (805 nm) in reducing the bacterial concentration in periodontal pockets. A comparison between the initial and the final bacterial counts revealed that irradiation with the diode laser facilitates considerable bacterial elimination, especially of A.actinomycetemcomitans, from periodontal pockets.

Moritz etal. 1998 investigated the long-term effect of diode laser therapy on periodontal pockets with regard to its bactericidal abilities and the improvement of periodontal condition. The results showed that the bacterial reduction with diode laser therapy was significantly better than in the control group.

Sakuri etal. 2000 described that periodontal diseases are an inflammatory condition caused by the presence of bacteria. The results indicated that the irradiated cells did produce considerably less prostaglandin E2 and cyclooxygenase, indicating the possible anti-inflammatory role of diode laser, which may have a therapeutic effect on the aggravation of gingivitis and periodontitis.

Yilmaz S etal. 2002 aimed to describe short-term results on selected microbiological and clinical parameters obtained by treatment with soft laser. The result showed that only the SRP/laser and SRP groups provided significant reductions in the proportions of obligate anaerobes before and after treatments.

Kreisler etal. 2005 conducted an in vitro study to examine the clinical efficacy of semiconductor laser periodontal pocket irradiation as an adjunct to conventional SRP. This investigation showed that the teeth treated with the laser revealed a significantly higher reduction in PT, PPD, and CAL.

Sharaf etal. 2012 stated that SRP with diode laser therapy was effective than SRP alone in the chosen patients, and antibacterial effect continued to be significant up to 6 weeks after therapy.

Study design

Twenty subjects satisfying the inclusion criteria were randomly assigned into two groups with an equal number in each.

Patients of both groups were put on meticulous oral hygiene regimen, and the oral hygiene maintenance was monitored throughout the study period. After taking subgingival plaque sample from the deepest pocket [Figure 1] thorough SRP was performed in both groups. Following SRP, Group II underwent laser irradiation with 940 nm diode laser by 300 μm optic fiber which was moved in the coronoapical direction of the pocket in parallel paths. The periodontal pockets of all patients were lased at an output power of 2.5 W, a pulse duration of 10 ms for 30 s, and a frequency of 50 Hz [Figure 2] and [Figure 3]. The patients were asked not to rinse or eat and drink for 30 min till the plaque sample was procured. The assessment of clinical Parameters was carried out at baseline, day 30, 90, and 180. The Microbiological Analysis was done before the start of the treatment at baseline, day 15, 30, 90, and 180, respectively [Table 1],[Table 2] and [Table 3].

Figure 1: Plaque collection with paper point for microbiological sampling

After diagnosis, prior to the start of the treatment, the supra-gingival plaque was gently procured. A sterile paper point (no 30) was introduced in the sulcus as far apically as possible and left undisturbed for 10 s following this; the paper points were inoculated in duplicates on 5% sheep blood with Columbia agar as a base [Figure 4]. One plate was incubated at 37°C under strict anaerobic conditions by anaerobic gas pack (Himedia) for the growth of anaerobic bacteria while other culture plates was incubated at 37°C under aerobic conditions [Figure 5]. Both the culture plates were incubated for 48-72 h. After 72 h of incubation, subculture of anaerobic plate was done again on anaerobic blood agar for pure isolation. Final identification was done by Viteck-2 automated identification system using ANC cards.

A significant reduction in the colony count of A.actinomycetemcomitans and P.intermedia was observed in both groups following interventions

The extent of reduction in all the parameters (Clinical parameters and microbial count) was significantly higher in SRP + diode laser treatment group as compared to SRP alone group.

Discussion

The primary cause of periodontitis is bacterial deposits on tooth surface (microbial plaque). [1],[2] Marker bacteria, for example, Actinobacillusactinomycetemcomitans, P.intermedia (P.i.), and Porphyromonas gingivalis are among the highly pathogenic bacterial spectrum of these deposits. Recently, the use of laser has emerged as an adjunctive procedure in enhancing the clinical outcome of the periodontal treatment [Table 4],[Table 5] and [Table 6]. [4],[7]

Table 4: Comparison of Clinical Attachment Level between two groups at different time intervals

Diode laser is a solid-state semiconductor laser that typically uses a combination of gallium arsenide and other elements such as aluminum and indium to change electrical energy into light energy. The range of wavelength is about 800-980 nm. Laser light at 800-980 nm is highly absorbed in hemoglobin and other pigments. [5],[8]

It is indicated for the treatment of soft tissues, therefore, it may be useful as an adjunct to SRP. Secondary effects include increased lymphatic flow, production of endorphins, increased microcirculation, stimulation of immune response, pain relief, and faster wound healing. [7],[9]

In this study, the selection of cases with mild to moderate periodontitis was done as severe forms of periodontitis are often accompanied with other systemic disorders and complications which might have a detrimental effect on the periodontium. [10],[11],[12]

The microbiological culture was chosen for this study because it is the gold standard method for identification and counting of the colonies. [13] Microbiological sampling, especially when used in conjunction with clinical trials, complements the diagnosis, and corroborates the results of the research. [14],[15]

All the periodontal indices were found to be higher in SRP alone group as compared to diode laser group on day 30, day 90, and day 180 intervals respectively which were statistically significant too. Thus, showing the better efficacy of Group II as compared to Group I in inhibiting the plaque accumulation in the short term (day 30), mid-term (day 90) as well as long-term (day 180). In this study, better response to diode laser treatment group could be attributed to use of diode laser at multiple intervals and the possible explanation for this could be bio-stimulation of soft tissue. With respect to the impact of diode laser on microbial flora of the affected teeth, the present study showed a significant reduction in colony count of both the pathogens evaluated. The wavelength of the diode laser is absorbed by protohemin and protoporphyrin IX pigments of the pigmented anaerobic perio-pathogens which lead to vaporization of water and causes lysis of the cell wall of the bacteria, leading to bacterial cell death. [16]

On a cellular level, metabolism is increased, due to bio-stimulation caused by diode laser thus increasing the production of adenosine triphosphate, the fuel that powers the cell. This increase in energy is available to normalize cell function and promote tissue healing. [17] Its role in wound healing has also been enumerated to hemostasis and coagulation. [18] which eventually results in a better periodontal health.

In both the groups, maximum reduction in colony count was observed between baseline and after intervention and minimum between baseline and day 180. In Group I, no significant difference in microbial count of two species was observed at any time interval. In Group II, no significant difference in microbial count of two species was observed at any time interval except at day 180, when mean A.actinomycetemcomitans count was significantly lower as compared to that of P.intermedia count (P = 0.036). Thus, a reduction of A.actinomycetemcomitans by laser therapy can be attributed to the destruction of critical virulence factors (lipopolysaccharide and proteases) present in the bacteria. [19] Based on the fact that the wavelength of diode laser has a better penetration and affinity for the chromophores (pigments) present in P. gingivalis thus resulting in the lysis of cell wall of these bacteria. [20]

The present study is a contributory evidence showing the better efficacy of adjunctive diode laser treatment in short-term (day 30), mid-term (day 90) as well as long-term (day 180) both clinical as well as microbial reduction in the oral environment. Hence, it can be considered a safe co-adjuvant in nonsurgical treatment of chronic periodontitis.

Conclusion

In the present study, an attempt was made to evaluate the adjunctive role of diode lasers on plaque index, gingival index, pocket probing depth, level of clinical attachment and microbial count in relation to scaling and root planning using a case-control design.

On the basis of these findings, adjunctive treatment with diode laser at a higher but clinically safe frequency (940 nm) at repeated regular intervals showed a better efficacy in ensuring a better periodontal health as compared to SRP alone. The results obtained in the present study were promising and prompt us to look further therole of repeated diode laser treatment in order to ensure better results of periodontal treatment.

However, with a further evaluation on the optimization of both dose (frequency in nm) and frequency (number of treatments) in larger sample size and in varying simulations should be carried out in future for corroboration of results..